ML20063N182

Interim Deficiency Rept Re Westinghouse Undetectable Failure Mode Which Could Exist in Online Testing Circuits for Solid State Protection Sys.Initially Reported on 820805.Next Rept to Be Filed by 830114

ML20063N182
Person / Time
Site:	Marble Hill
Issue date:	09/07/1982
From:	Shields S PSI ENERGY, INC. A/K/A PUBLIC SERVICE CO. OF INDIANA
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
10CFR-050.55E, 10CFR-50.55E, S82-18, SUP-0019, SUP-19, NUDOCS 8209200068
Download: ML20063N182 (2)

Text

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PUBLIC SERVICE INDIANA S. W. Shields September 7, 1982 semor v,ce Presuient S82-18 -

Nw Wr Dmsion SVP-0019 Mr. James G. Keppler, Docket Nos.: STN 50-546 Regional Administrator STN 50-547

) U.S. Nuclear Regulatory Commission Construction Permit Nos.:

i Region III CPPR - 170 799 Roosevelt Road CPPR - 171 Glen Ellyn, Illinois 60137 Marble Fill Nuclear Generating Station - Units 1 and 2

Dear Mr. Keppler:

4 On August 5, 1982, Mr. T. D. Geib of Public Service Company of Indiana, Inc. (PSI) notified your office of a potentially reportable item as required by 10 CFR 50.55(e). Westinghouse identified an undetectable failure mode which could exist in on-line testing circuits for their Solid State Protection System (SSPS).

1 Periodic testing of the SSPS includes actuation of master relays which actuate Safeguards systems. When a preselected master relay is energized, a proving lamp in series with the output (slave) relay coil confirms electrical continuity. Operation of the relay is prevented by reducing the i coil voltage from 120VAC to 15VDC during the test. Subsequent tests from the Safeguards Test Cabinets energize each output relay to confirm actuation of the Safeguards device. In those instances where actuation of the final device would disrupt plant operation, a proving lamp verifies

relay contact movement, field wiring, and electrical continuity through the final device.

As mentioned above, output relay coil continuity is confirmed, without operating the relay by reducing the circuit voltage to 15VDC from 120VAC.

Operation of the master relay by means of the pushbutton test switch also removes the shunt from the proving lamp and allows the 15VDC to energize it to confirm continuity through the output relay coil.

j K0 $k6 PDR SEP. 1 3 H E P. O. Box 190, New Washington, Indiana 47162 812. 289 .3000

4 PUBUC SERVICE

] lbEMANA Mr. James G. Keppler September 7, 1982 Upon completion _of the master relay and output relay coil continuity tests, j 120VAC circuit voltage'is restored. However, if the switch contacts which

' shunt the proving lamp should fail to reclose as expected, 120VAC would be applied to the proving lamp in the event the system were called upon to

! operate. Since plant operacors would receive no indication of the i contacts' failure to reclose, this situation might remain undetected.

Depending on the output relay coil impendance and the number of output relays being operated by the master relay contacts, the current through the

, proving lamp could cause it to burn'open before the output relays energized. In such an instance, associated Safeguards devices in the affected train would not actuate. Westinghouse is reviewing this item to determine alternatives in design changes.

j ,This letter is intended to fulfill the requirements of an interim report as required by 10 CFR 50.55(e). A further report will be filed on or before January 14, 1983. If you have any questions, please feel free to contact J me.

Sincerely, W*

S. W. ' Shields V

1 4

SWS/TDG/jl i

cc: Director of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C. 20555 i

J. E. Konklin J. J. Harrison i

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